Sublime deprecation errors prevents linting

[spotiris]

This issue addresses #1 #2 : deprecation errors appear in Sublime 3 which prevent the operation of this package.

Thankfully the @rgant has fixed it in their fork: https://github.com/rgant/SublimeLinter-contrib-dockerfilelint.git .

To use the fixed fork:

~/.config/sublime-text-3/Packages/
git clone --single-branch --branch fix/deprecation-warnings https://github.com/rgant/SublimeLinter-contrib-dockerfilelint.git

You must also install "Dockerfile Syntax Highlighting" via package control, then restart Sublime.

[nodesocket]

Would be awesome to get the fix backported into this repo.